Breechbolt lock for automatic firearms



y 9, 1957 B. MAILLARD 2,798,415

BREECHBOLT LOOK FOR AUTOMATIC FIREARMS Filed D80. 18, 1955 2 Sheets-Sheet l MAW/P0 Mmmw,

QM WTmRfi/Ef V July 9, 1957 B. MAILLARD BREEOHBOLT LOCK FOR AUTOMATIC FIREARMS 2 {Sheets-Sheet? Filed Dec. 18, 1953 ll- -llllmm United States Patent Ofifice BREECHBOLT LOCK FOR AUTOMATIC FIREARMS Bernard Maillard, Geneva, Switzerland, assignor to Company Brevets Aero-Mecaniques S. A., Geneva, Switzerland, a society of Switzerland Application December 18, 1953, Serial No. 399,127

Claims priority, application Luxemburg December 24, 1952 3 Claims. (Cl. 89129) The present invention relates to automatic loading firearms (this term including, in the following specification and claims, semi-automatic firearms the reloading of which takes place automatically but the firing of which is performed manually for every shot, fully automatic firearms firing by bursts and firearms capable of working either semi-automatically or automatically) in which the movable breech-block is temporarily locked in its barrel closing (i. e. frontward end) position by a movable system capable, once the breech-block has reached said end of its frontward stroke, of sliding with respect to said breechblock so as temporarily to prevent unlocking thereof.

In such firearms, said sliding system cooperates with the locking piece which holds the breech-block in said position in the following manner:

Elastic return means first drive toward the front the whole of the breech-block, its locking piece and the sliding system.

Then, when the breech-block stops at the end of its frontward stroke, the sliding system has a supplementary frontward movement in the course of which it keeps the breech-block locking piece in active position. At the end of this supplementary frontward movement, a shot is fired, generally by a firing pin carried by the sliding system.

Then the sliding system is pushed back by gases under pressure fed from the firearm barrel at .the end of said supplementary stroke, and this recoil movement of the sliding system enables the locking piece, to be retracted into inactive position, whereby the breech-block -is released.

Thebreech-block and its locking -piece then slide in the rearward direction.

Of course it is advantageous, in firearms of this kind, to provide safety meanscapable of-preventing accidental rebounding of the sliding system. As a'matter of fact, such r'eboundings, if of suflicient amplitude, might cause the sliding system to release the breech block locking piece, which would be particularly dangerous in the-case of'missfire.

According to my invention, I: provide a weight mounted in oscillating fashion in the'breech-case and means for transmitting'thereto, by a shock, a substantial-portion of the kinetic energy of the sliding system during every supplementary stroke thereof, so as tozreduce rebounding of said system when it strikes its front abutmentatthe end of each of said supplementary strokes,:means for damping the oscillations of said weight being provided to-reduee the kinetic energy thereof to a negligible'valueiwhenwsaid shock transmitting means again connectLthe weight with the sliding system during the return movement thereof after its limited rebounding, whereby the weight gives back to the sliding system practicallymothing of the energy it had received therefrom.

Preferred embodiments of the present invention .will be hereinafter described with reference/to the. accompanying: drawings, ,given merely :by way .of example, ..and "in which:

Patent ed July 9, 1957 Fig. 1 is an elevational view with parts cut away of the breech mechanism of an automatic firearm made according to my invention.

Fig. 2 is a cross section on line IIII of Figs. 1 and 3'.

Fig. 3 is a diagram showing in plan view the sliding system included in said breech mechanism, this system being shown in position with respect to the side walls of the breech-case supposed to have been cut on the line III-III of Fig. 2.

Finally, Figs. 4 and 5 are an explanatory diagram and a curve which will be hereinafter referred to.

The firearm is of any suitable conventional construc: tion. For instance, it includes a barrel 1 rigid at the rear with a breech-case 2 in which is mounted, slidable Parallel to the firing axis, a movable breech-block 3 subjected to the action of a recuperator spring 4 which constantly urges it frontwardly. The breech-block is provided with a locking piece 5 adapted to engage a surface 5a rigid with the breech-case so as to lock the breech-block safely in end front position whenthe shot is being fired.

Now, in order to keep looking piece 5 temporarily .in this active position, I make use of a sliding system including two sliding plates 6 disposed on either side of breechblock 3, between said breech-block and breech-case 2, these plates being connected at the front by a cotter 7 against which bears recuperator spring 4. The firing pin is carried by said cotter 7 which extends through an elongated passage 8 provided in the breech-block, whereby the sliding system can have relative displacements with respect to the breech-block. During the beginning of the frontward stroke of the breech-block, its locking piece 5 holds the sliding system in rear position relatively to the breech-block, that is to say cotter 7 is held at the rear end of elongated slot 8. When the breech-block has reached the end of its frontward stroke, locking piece 5 is moved down into active position, i. e. into engagement with shoulder 5a, thus releasing sliding plates 6 which can thus have a supplementary frontward displacement of a length represented by a on Fig. 4, so as to bring suitable portions of. slide plates 6 over looking piece 5 which is thus held in its active position as shown by Fig. 1.

After the shot has been fired, a gas tap control system (the driving portion of which is not shown on the drawing) acts upon slide plates 6 through a fork 9 and pushpieces 10 so as to impart a recoil movement to said slide plates.

If no special precautions were taken, slide plates 6, upon striking their front abutment, might rebound rearwardly with an amplitude equal to ,or higher than a, which would result in an accidental unlocking of breechblock 3.

-In .order to reduce the risks of such a rebounding, I provide safety means which, according to my invention, are as follows:

Idispose across the path of movement of at leastone element rigid with the sliding system, for instance across the :paths followed respectively by two projections 11 disposed symmetrically on the external face of each slide plate '6, an abutment 12 movable with respect to breechcase 2, this movable abutment being disposed in .such manner that it is struck by the corresponding projection :11 when slide plate :6 has still to move imthe frontward direction a distance "r at most equal to and preferably smaller-than the complementary stroke a ofslideplates 6 after breech-block 3 has reached its front endposition.

Eaehabutment 12 is operatively connectedto a weight 13 itself movably guided in the breech-case between a front abutment 14 and a rear abutment 15. Advan tageously, as it will be hereinafter supposed, abutment *12 is rigidwith weight 13 and the whole of said-abutment and said weight is guided so as .to moveparallel-tothe-dis I placement of slide plates 6.

Each weight 13 cooperates with an elastic system, such as a spring 16, urging said weight 13 toward its rear abutment 15.

I provide, for each weight 13, a play or maximum amplitude of displacement "b higher than the residual stroke "r" above referred to.

Now, account being taken of the mass of the sliding system, of its speed when it strikes the abutments 12 of weights 13 and of the characteristics of spring 4, I deter mine amplitude b, the mass of said weights 13 and the characteristics of springs 16 in such manner that, on the one hand, when the projection 11 of a sliding plate comes into contact with the abutment 12 of the corresponding weight 13, this weight is projected against its front abutment 14 from which it rebounds and, on the other hand, when said weight comes back to strike its rear abutment 15, slide plates 6 have themselves rebounded from their own front abutment 17 and have already moved back of a distance "11" greater than the residual stroke r.

By way of example, it may be indicated that in a particular case, the residual stroke r has been given a value of 0.4 mm. and amplitude 71" a value equal to 3.35 mm.

Fig. 4 diagrammatically shows the essential elements of such a breech mechanism the operation of which is illustrated by the diagram of Fig. 5 on which I have plotted in abscissas the times (in seconds) and in ordinates the displacements (in millimeters). The solid line curves show the movement of weights l3 and the dotted line curve the movement of slide plates 6.

l The operation of said breech mechanism is then as folows:

When breech-block 3 reaches the end of its frontward stroke, that is to stay when it is in barrel closing position, slide plates 6 can still move frontwardly a distance equal to their supplementary strokes a. When they have moved forward a distance such there still remains a residual stroke "r" before they reach their limit front position, projections 11 come into contact with the abutments 12 of weights 13 (position shown by Fig. 4). This time corresponds to point A of the diagram of Fig. 5 on which the three horizontal lines correspond respectively to the front abutments 14, the rear abutments 15 of weights 13 and the front abutment 17 of slide plates 6. Weights 13 are then thrown frontwardly; they leave their rear abutment 1S and abutments 12 loose contact with projections 11 (position shown by Fig. 3). Weights 13 finally come to strike their front abutment 14 (point B of dia gram of Fig. 5). In the meantime, slide plates 6 the movement of which has been slowed down by their impact against weights 13 have come to strike their front abutment 17 (point C of the diagram) and have startedrebounding rearwardly. As for weights 13, after they have struck their front abutment (point B), they also reboundv rearwardly until they again strike their rear abutment 15 (point D). But at this time, the projections 11 of slide plates 6 are out of reach (point B) of abutments 12 and weights 13 start back frontwardly without having had the possibility of giving back energy to slide plates 6. The movement of said slide plates is then damped by spring 4, whereas that of weights 13 is damped by springs 16. Thus, when said weights again come into contact with said slide plates (point F), they no longer have enough energy to risk producing a dangerous rebounding of the slide plates toward the rear.

To sum up, the essential characteristic of this operation is that weights 13 collect from the sliding system, when they first come into contact therewith, an amount of energy suflicient to prevent said sliding system from rebounding dangerously toward the rear after striking its front abutment, and that said weights do not come again into contact with said sliding system until they have lost most of the energy collected during their initial contact therewith.

It should be noted that the movement of weights 13 might take place in directions other than parallel to that 4 of the sliding system, in which case instead of. providing abutments 12 rigid with the weights, 1 might interpose, between these parts, an operative connection adapted to transmit to the weights the shock received by the abutments.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efiicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An automatic loading firearm which comprises, in combination, a breech-case, a reciprocating breechblock slidable longitudinally in said breech-case between a front and a rear position with respect thereto, a locking piece carried by said breech-block movable transversely with respect thereto between an active and a retracted position and arranged to cooperate, in said active position, with said breeclrcase to lock said breech-block in said front end position temporarily for the firing of every shot, an inertia operative sliding system carried by said breech-block movably with respect thereto between a front and a rear position, resilient means between said breech-case and said sliding system for urging said sliding system in the frontward direction, means carried by said sliding system for holding said locking piece in said active position thereof as long as said sliding system is ahead of said rear position thereof with respect to said breech-block, at least one weight mounted for oscillation in said breechcase and mounted independently of but freely movable with said-sliding system, shock transmitting means operatively connected with said weight disposed across the path of travel of said sliding system and positioned to be struck by said sliding system when said breech-block is in said front position thereof and said sliding system is moving frontwardly with respect to said breech-block, to transmit kinetic energy from said sliding system to said weight, and means including abutments carried by said breech-case and at least one spring interposed between said breech-case and said weight for absorbing most of the kinetic energy of said oscillating weight before said shock transmitting means are again struck by said sliding system.

2. An automatic loading firearm which comprises, in combination, a breech-case, a reciprocating breech-block slidable longitudinally in said breech-case between a front and a rear position with respect thereto, a locking piece carried by said breech-block movable transversely with respect thereto between an active and a retracted position and arranged to cooperate in said active position with said breech-case temporarily to lock said breech-block in said front end position with respect to said breech-case for the firing of every shot, an inertia operative sliding system carried by said breech-block movably with respect thereto between a front and a rear position, resilient means between said breech-case and said sliding system for urging said sliding system in the frontward direction, means carried by said sliding system for holding said locking piece in said active position thereof as long as said sliding system is ahead of said rear position thereof with respect to said breech-block, at least one weight mounted for oscillation in said breech-case and mounted independently of but freely movable with said sliding system, at least one abutment mounted movable on said breech-case across the path of travel of a part of said sliding system and operatively connected with said weight, said abutment being-so located on said breech-case as to be struck by said sliding system when said breech-block is in said front position thereof and said sliding system is moving frontwardly with respect to said breech-block, to transmit kinetic energy from said sliding system to said weight, a front abutment for said weight carried by said breech-case, a rear abutment for said weight carried by said breech-case, and spring means between said breech-case, and said weight for urging said weight toward said rear abutment, the period of oscillation of said weight between said front and said rear abutment being a fraction of that of said sliding system as it rebounds from its front position, whereby most of the energy imparted by said sliding system to said weight is absorbed by said breech-case during the oscillating movement of said weight before said first mentioned abutment is again struck by said sliding system.

3. An automatic loading firearm which comprises, in combination, a breech-case, a reciprocating breech-block slidable longitudinally in said breech-case between a front and a rear position with respect thereto, a locking piece carried by said breech-block movable transversely with respect thereto between an active and a retracted position and arranged to cooperate in said active position with said breech-case temporarily to lock said breechblock in said front end position with respect to said breech-case for the firing of every shot, an inertia operative sliding system carried by said breech-block movably with respect thereto between a front and a rear position, resilient means between said breech-case and said sliding system for urging said sliding system in the frontward direction, means carried by said sliding system for holding said locking piece in said active position thereof as long as said sliding system is ahead of said rear position thereof with respect to said breech-block, at least one weight mounted for reciprocation in said breech-case in a direction parallel to that of the movement of said breech-block, said weight being mounted independently of but freely movable with said sliding system, at least one abutment mounted rigid with said weight across the path of travel of a part of said sliding system, said abutment being so located on said breech-case as to be struck by said sliding system when said breech-block is in said front position thereof and said sliding system is moving frontwardly with respect to said breech-block, to transmit kinetic energy from said sliding system to said weight, a front abutment for said weight carried by said breech-case, a rear abutment for said weight carried by said breech-case, and spring means between said breech-case and said weight for urging said Weight toward said rear abutment, the period of oscillation of said weight between said front and said rear abutment being a fraction of that of said sliding system as it rebounds from its front position, whereby most of the energy imparted by said sliding system to said weight is absorbed by said breech-case during the oscillating movement of said weight before said first mentioned abutment is again struck by said sliding system.

References Cited in the file of this patent UNITED STATES PATENTS 1,771,311 Phliponeau July 22, 1930 2,361,985 Birkigt NOV. 7, 1944 2,451,624 Loomis et a1. Oct. 19, 1948 2,536,997 Lippert et al Jan. 2, 1951 FOREIGN PATENTS 678,425 Great Britain Sept. 3, 1952 

